1. Field Of The Invention
The present invention relates to an electrical connector useful for signal transmission and reception between a memory card and the circuit of a machine concerned, and more particularly to a mechanism to effect ejection of the memory card from a header providing electrical connection to the circuit through use of a cam lever engaging a cam surface which force multiples the hand force without causing accelerated memory card action to throw the card out.
2. Description of Prior Art
In the electrical connector industry, it is well known to provide an electrical connector useful for signal transmission and reception between a memory card and the circuit of a machine concerned. The Personal Computer Memory Card International Association ("PCMCIA") has established memory card (or "PC Card") standards defining the PC Card's physical outline standards, connector system and qualification test parameters, including reliability, durability and environmental test parameter, PC Card Standard, Release 2.0, PCMCIA (September 1991), which is hereby incorporated by reference.
In more detail, an electrical connector includes a pin header to act as pin shrouds protecting an array of pin terminals which receive the memory card and engage the circuit as well as provide polarization for the memory card. The electrical connectors are held in the pin header by frictional engagement between the female contacts carried by the memory card (or IC pack or PC card), and the male pins carried by the pin header. A tight fit is necessary for ensuring proper frictional engagement of the pin header and the contacts of the memory card. Because the pin headers are relatively easily damaged, it becomes necessary to maintain a proper alignment of the memory card (or PC card) when engaging or disengaging with the pin contacts.
To disengage the memory card from the pin header, the sum of the frictional engagement forces of all of the numerous contacts require that a substantial friction force must be overcome during the un-mating operation. In such instances, it is often desirable to have an ejection means to help eject the connector from the pin header. Thus, there has been a need for an ejection device wherein a sufficient force is applied to disengage the memory card from the pin header, while at the same time maintaining linear alignment of the memory card to prevent damage to the pin header contacts as well as protect the card from being ejected and completely out onto the floor. Many prior attempts to satisfy this need have been suggested in the prior art.
Typical of such prior attempts is U.S. Pat. No. 4,178,051 issued to Kocher et al. which describes a latch/eject pin header (10) which provides for positive locking of the connection of a header and positive ejection of the connector upon disconnect. The header includes an elongated housing defining a elongated cavity (14) therein with a plurality of pin terminals (20) fixed in the base of the cavity. Latching members (28) pivotly mounted at the ends of the cavity include a latching arm for engaging the mating connector, an eject arm (36) for levering the connector from the cavity, and an actuating arm (38) to effect pivotal movement of the latching member (28).
In the embodiment shown in FIG. 4 of Kocher et al., a two piece actuation member includes an actuating member (58) having a pin mounted thereon engaging a recess (56) of a latching arm (50) and a cam surface (62) on the free end thereon. Inward movement of the actuation member (58) causes the cam surface (62) to engage an end portion of the mating face (44) of the connector to cam it out of the mating engagement with the terminal pins (20) of the header (10).
Another example of such an ejection device is described in U.S. Pat. No. 4,875,873 issued to Ishizuka et al. In Ishizuka, a multi-terminal connector composed of a male housing (9) and a female housing (1) is disclosed wherein each housing member (1,9) is provided with a plurality of female and male terminals respectively. The housing members can be connected or disconnected from each other by a relatively strong force owing to a cam mechanism integrated therein. The cam mechanism (as illustrated in FIGS. 2,3,4) includes guide rails (4,4') on the female housing (i) to define slots (5), and cam tracks (13,13') formed on the male housing (9). A pair of sliders (15) has grooves defined to engage the guide rails (4,4'), a cam follower (19) which extends through the slots (5,5') to engage the cam tracks, and a pin (20) which is engagable pin guide grooves formed in a rotary actuator plate (21). As shown in FIGS. 2-4, a handle (24) of the rotary guide plate (21) is rotated about axis (22), which fits within axis (7) of the female housing (1), and the pin (20) follows the contour of pin guide grooves (23,23') to move cam follower (19) along the slots (5) and along cam tracks (13,13'). This motion of the handle (24) causes the connection and disconnection of the female and male housings (1,9) which guide shafts (8) formed on the female housing (1) engage corresponding female portions (14) of the male housing to ensure proper alignment therebetween.
While such devices provide the important advantages of proper alignment and the use of leverage to increase applied force in an ejection technique, they do not provide the advantage of multiplying the applied hand force to maximize mechanical leverage through the utilization of cam surfaces which induce the coordination of both linear and rotational forces to eject the connector from the pin header, wherein the ejector is a self contained integrated unit requiring no specialized surfaces on the substrate or memory card being ejected.